Rack and gear spring charging means for reciprocating contact

ABSTRACT

Disclosed is circuit interrupting apparatus of the type including a pair of coaxially disposed electrically conductive contact carrier rods, one of the carrier rods mounted for reciprocative movement between a closed position whereby the carrier rods are engaged, and an open position whereby the carrier rods are disengaged, and the current flow therethrough is interrupted. Improved actuator apparatus for translating the movable carrier rod into and out of engagement with the other contact carrier rod includes a pair of racks operatively coupled by rotary gears, the racks mounted for reciprocating motion in respective parallel linear paths. One of the racks is coupled to a gear and rotary shaft arrangement for urging the rack forward to compress a closing spring coupled thereto, a latch and roller keeper arrangement temporarily holding the closing spring compressed. Another latch arrangement engages the operatively coupled rotary gear against linear motion when the closing spring is compressed, tripping means coupled to the rotary shaft then releasing the compressed closing spring, the rearward movement of the one rack powering the other rack coupled to the reciprocating contact carrier rod forward to close the contacts. An opening spring coupled to this rack is then compressed by the forward movement of the rack. The opening spring is then automatically released from compression by latch release means coupled to relay circuitry responsive to excessive current through the apparatus, or manually released by latch release means operatively coupled to the rotary shaft.

United States Patent [72] Inventors James E. McClain;

Argus F. Parks, both of Greenville, Tex. [2]] Appl. No. 22,554 [22] Filed Mar. 25, 1970 [45] Patented Jan. 4, 1972 [7 3] Assignee Esco Manufacturing Company Greeuville, Tex.

[54] RACK AND GEAR SPRING CHARGING MEANS FOR RECIPROCATING CONTACT 10 Claims, 12 Drawing Figs.

[52] 11.8. CI ..200/153SC, 200/78, 200/153 P [51] Int. Cl Hlh 3/30, HOlh 3/40, HOlh /06 Field of Search 200/153 P, 153 SC, 78,144 B; 335/171, -77

[56] References Cited UNITED STATES PATENTS 3,098,134 7/1963 Nijland 200/78 2,539,213 l/l Von Mehren 200/153 P 1,837,544 12/1931 Haller 200/78 1,380,595 6/1921 Ritz, Jr. 200/78 FOREIGN PATENTS 462,425 6/1928 Germany 200/153 P Primary Examiner-Robert K. Schaefier Assistant ExaminerRobert A. Vanderhye Attorney-Kenneth R. Glaser ABSTRACT: Disclosed is circuit interrupting apparatus of the type including a pair of coaxially disposed electrically conductive contact carrier rods, one of the carrier rods mounted for reciprocative movement between a closed position whereby the carrier rods are engaged, and an open position whereby the carrier rods are disengaged, and the current flowv therethrough is interrupted. Improved actuator apparatus for translating the movable carrier rod into and out of engagement with the other contact carrier rod includes a pair of racks operatively coupled by rotary gears, the racks mounted for reciprocating motion in respective parallel linear paths. One of the racks is coupled to a gear and rotary shaft arrangement for urging the rack forward to compress a closing spring coupled thereto, a latch and roller keeper arrangement temporarily holding the closing spring compressed. Another latch arrangement engages the operatively coupled rotary gear against linear motion when the closing spring is compressed, tripping means coupled to the rotary shaft then releasing the compressed closing spring, the rearward movement of the one rack powering the other rack coupled to the reciprocating contact carrier rod forward to close the contacts. An opening spring coupled to this rack is then compressed by the forward movement of the rack. The opening spring is then automatically released from compression by latch release means coupled to relay circuitry responsive to excessive current through the apparatus, or manually released by latch release means operatively coupled to the rotary shaft,

leg

| e4 65 ill 82 PATENTEBJM 4 l/V VEW TORS JAMES E. McCLAIN ARGUS F. PARKS ATTORNEY SHEET UF 3 INVENTORS JAMES E. McCLAIN ARGUS F. PARKS ATTORNEY PATETEU JAM d I972 :1 mm Ow mm M 4 SHEET b 0F 4 hm Q1 m3 OON Ow INVENTORS JAMES E. McCLAlN ARGUS F.- PARKS ATTORNEY RACK AND GEAR SPRING CHARGING MEANS FOR RECIPROCATING CONTACT This invention pertains to circuit interrupting apparatus, more particularly to actuating mechanism for reciprocating coaxially disposed contact carriers of circuit interrupting apparatus into and out of engagement with one another, and even more particularly to a rack and gear arrangement for powering a drive shaft coupled to a contact carrier rod in both the opened and closed directions.

Within the electric power industry, there is a continuing need for newer and more sophisticated devices to protect high-power equipment in the event that the currents therein become excessive. Various types of protective devices, such as fused or circuit breakers have been designed for this purpose, all such devices suffering one or more disadvantages.

It is therefore a primary object of the invention to provide new and improved circuit interrupting apparatus of the type to be inserted into external circuit means whose current is to be interrupted.

It is another object of the invention to provide a new and improved actuator mechanism for opening and closing reciprocatively mounted contact carrier rods disposed within a vacuum bottle or interrupter.

It is a further object of the invention to provide new and improved actuating mechanism of circuit interrupting apparatus for powering a reciprocatively mounted contact carrier rod into contact with a fixed contact carrier rod where the entire apparatus is trip-free and may consequently be opened at any time in response to excessive currents or faults detected by said apparatus.

It is a still further object of the invention to provide an improved actuating mechanism for powering a reciprocatively mounted contact carrier rod in the closed and opened position, the requisite power be initially stored by spring compression means which, when released, advances the carrier rod into engagement with a fixed contact carrier rod, trip release means responsive to excessive current conditions tripping the movable carrier rod open, thereby to interrupt the circuit in which the carrier rods are disposed.

In accordance with these and other objects, the present invention is directed to actuating mechanism coupled to one of a pair of coaxially disposed contact carrier rods, the actuating mechanism reciprocatively translating the one carrier rod into and out of engagement with the other contact carrier rod, thereby to respectively close and open" the circuit in which the carrier rods are electrically connected. The actuator mechanism comprises a pair of racks adapted to reciprocate in parallel linear paths, pinion gear means operatively coupling the racks together. As one of the racks is urged forward in response to the rotation of an operating shaft coupled to that rack, a closing spn'ng coupled to that rack is compressed and temporarily held in the compressed condition by latch means engaging a roller keeper on the forwardly urged rack. Simultaneously, the pinion gear means is latched against linear travel, thereby operatively coupling the racks together. Trip release means responsive to the rotation of the operating shaft disengages the latch from the first rack; the closing spring thereafter powering the first rack rearward, the other rack consequently being urged forward to force the movable contact carrier rod into engagement with the other contact carrier rod, thus closing the circuit. The forward movement of the other rack then compresses an "opening spring coupled thereto. A trip release mechanism responsive to excessive current through the contacts, or to the manual rotation of the operating shaft then disengages the latch from the pinion gear means, thereby to power the reciprocatively mounted contact carrier rod into disengagement, and opening" the current.

Other features, advantages, and objects of the invention will become more readily understood from the following detailed description taken in conjunction with the attached drawings, where identical numerals refer to similar parts, and wherein:

FIG. 1 is an overall view. of circuit interrupting apparatus of the type to be electrically coupled into external circuit means, which current is to be interrupted;

FIG. 2 is an overall partially broken away perspective view of the actuating mechanism coupled to the reciprocating contact carrier rod illustrated in FIG. 1;

FIGS. 3, 7, and 10 are top views of the actuator mechanism illustrated in FIG. 2 and the coaxially disposed contact carrier rods, schematically illustrating the various cycles of operation thereof;

FIGS. 5, 9, and 12 are partial side elevational views taken along the line 5-5 of FIG. 3 schematically illustrating the latch mechanism for one of the racks in various cycles of operation thereof;

FIGS. 4, 8 and II are top views of another latch mechanism disposed on the cover plate illustrated in FIG. 2, schematically illustrating the various cycles of operation thereof; and

FIG. 6 is a perspective view of the operating shaft and drive means for urging one of the racks forward.

Referring now to the drawings, and initially to FIG. 1, there is depicted an overall view of circuit interrupting apparatus 10. The apparatus 10 generally includes a vacuum bottle or interrupter 20, generally known by those skilled in the art, a pair of coaxially disposed electrically conductive contact carrier rods 21 and 22 extending therein with electrical contacts 23 at the end face of each rod. One of the rods 21 extends through an end wall of the substantially evacuated chamber 20 and may be rigidly or immovably connected with an enlarged terminal portion 25. The other rod 22 extends through an opposite wall of the interrupter 20 and is mounted for reciprocative movement between a closed" portion, whereby the contact faces 23 are in engagement with one another, and an open" position (as shown in FIG. ll) whereby the contact faces 23 are disengaged. The axially movable rod 22 extends into the housing 30 and is coupled therein to actuating mechanism 40 (FIG. 2) of the present invention for reciprocatively translating the carrier rod 22. The rod 22 has a lug member 31 connected thereto to which one or more current carrying cables 32 have one end coupled, the other end of the current cables 32 being connected, for example, to an enlarged terminal portion 34 housing relay circuitry 35.

The entire apparatus 10 is ordinarily removably electrically connected into external circuitry (not shown) by way of enlarged terminal portions 25 and 34. When the contact faces 23 are engaged (the apparatus is in its closed" mode) uninterrupted current flows through the line by way of terminals 25 and 34, rods (and associated contacts) 20 and 22, and power cables 32. On the other hand, when an excessive current or fault is sensed by relay circuitry 35, the carrier rod 22 is tripped or translated open, disengaging the contacts 23 and interrupting the current. As subsequently described, the carrier rod 22 may also be manually tripped to the open position.

Referring now to the remaining figures, and initially to 106 2, there is now specifically described the details and features of the actuating mechanism 40 contained within the housing 30 and coupled to the reciprocating carrier rod 22. The housing 30 includes a pair of sidewalls 11 and 12, and a pair of front and rear end walls 14 and 15, respectively connected to a base plate 13. An intermediate wall 16 is disposed between and parallel to the end walls 14 and 15. A cover plate 17 is disposed over the housing and may be secured by conventional bolts to the sidewalls l1 and 12.

A drive rod 41 disposed coaxially of the contact carrier rods 21 and 22 is rigidly coupled at one end to the free end of the movable contact carrier rod 22, the drive rod 41 extending through a bushing 42 in an opening in the wall portion 16. The other end of the drive rod is joined to a short rack 45 by the collar 44. The drive rod 42 is thus mounted for reciprocative movement through and by the wall 16, which movement is effected by the forward and rearward motion of the rack 45. The rack 45 is thus fixedly connected to the drive rod 41 as well as to a rear shaft 46 which extends through, and can reciprocate within, an opening in the rear wall 15 of the housing 30.

Disposed between, and having respective ends abutting against, the wall portion 16 and the collar 44 is an opening" compression spring 50 surrounding the drive rod 42 which,

when free, drives the rack 45, drive rod 41, and contact carrier rod 22 in the rearward or open" position, all as subsequently described.

Extending through and reciprocatively mounted within a bushing 51 disposed within another opening in the intermediate wall portion 16 is another drive rod 52 rigidly coupled by way of collar 53 to one end of another relatively long rack 55. The other end of the rack 55 is also rigidly coupled to a rear shaft 56 which extends through and can reciprocate within an opening in the rear face of the housing 30.

A pair of screws 26 and 27 are provided within a rear plate 28, and may be respectively adjusted within the plate 28 to limit the rearward travel of the rods 46 and 56. A pair of pressure plates and 29 are secured to base 13 to provide auxiliary guidance to the reciprocating movement of the racks and 55, respectively.

A closing compression spring 60 having respective ends abutting against the wall portion 16 and the collar 53, is disposed around and supported by the drive rod 52, and serves to drive, when released, the rack (and drive rod 52) in the rearward direction. A bracket member 57 having upwardly extending flanges 58 and 59 is slidably mounted to the top face of the rack 55, the bracket 57 playing an integral part in releasing the spring 60 from compression, as subsequently described.

A pair of pinion gears 61 and 62 are disposed for simultaneous engagement or meshing with the racks 45 and 46, and are rotatably mounted to an overlying carriage plate 63 by way of pins 64 and 65, respectively. Secured to the top face of the carriage plate 63 and intermediate the pins 64 and 65 is a roller keeper 66. Another gear is disposed so as to have its teeth mesh only with the rack 55, the gear 70 including, as an integral portion thereof, an upwardly extending shoulder 71.

Operatively coupled to and journaled for rotation within the axial bore of the gear 70 is an operating shaft extending through the cover 17 and into the base plate 13, and having a protuberance or boss 72 adapted to engage the shoulder 71. As subsequently described, the gear 70 in cooperation with the operating shaft 80 provides the charging or loading function of the closing spring 60. A boss portion 76 rigidly attached to the shaft 80 by the collar 77 provides a tripping lever for both the manual closing and opening cycles of the actuating mechanism 40. The shaft 80 may be rotated in either the clockwise or counterclockwise direction by a handle (not illustrated) engaging the end 82 thereof.

At the underside of the cover plate 17 is a latch arm 101 pivotally mounted to the plate 17 by a pin 102, spring means 103 biasing the arm 101 in the counterclockwise direction. The latch arm 101 has a finger portion 104 adapted to engage the roller keeper 66 disposed at the top face of the carriage plate 63. Trip release means 105 is also pivotally mounted by way of pin 106 to the cover plate 17 and includes a cam surface 107 for engaging the latch finger 104, as pictured, to cam and hold the finger 104 in engagement with roller keeper 66. Pivotally coupled to the leg portion 108 of the trip release means 105 is an extension arm 110 having a projection 109 and a downwardly extending boss or toggle 111 abutting the leg portion 108 of the trip release means 105. The boss 111 is biased against the leg portion 108 by the spring means 120. A stop 121 limits the extent of counterclockwise rotation of the trip release means 105. Automatic tripping of the release means 105 may be effected by a wire coupled to solenoid means 131 coupled to the fault sensing or relay circuitry 35, (shown in FIG. 11).

Pivotally connected by way of pin 141 to the sidewall 11 of the housing 30 is another latch arm (FIGS. 2, 5, 9 and 12) having a latch finger 142 adapted to engage another roller keeper 143-secured to the side of the rack 55. Trip release means 145 is also pivotally mounted by way of a pin 146 to a plate 149 affixed to the sidewall 11, the means 145 including an extension 147 adapted to engage the flange 58. The release means 145 also includes a cam surface 148 for engaging the cam follower portion of the latch finger 142 to cam and hold the finger 142 in engagement with roller keeper 143. Spring means 150 biases the trip release means 145 in the clockwise or latched position.

The operation of the apparatus, and particularly the actuator mechanism 40, will now be described, beginning with the apparatus in its inactive state as shown in FIG. 3, the vacuum interrupter contacts 23 being opened. Accordingly, the shaft 80 is rotated in the counterclockwise direction (FIG. 6) until the boss 72 engages the shoulder 71. Further rotation of the shaft in this counterclockwise direction then similarly rotates the gear 70, and urges the rack 55 forward to compress the closing spring 60 between the collar 53 and the intermediate wall portion 16. V

The forward movement of the rack 55 causes the counterclockwise rotation of the gears 61 and 62 which consequently causes the carriage plate 63 to move in the same direction as, but at a lesser linear velocity than, the rack 55. Since the gears 61 and 62 (and carriage plate 63) are not fixed during this portion of the cycle, but are floating, they will roll freely along the teeth of the racks 45 and 55, and the rack 45 (and driven rod 41) will consequently remain stationary.

The rearward travel of the carriage plate 63 thus forces the roller keeper 66 into engagement with the latch finger 104, and the 'latch arm 101 is cammed in the clockwise direction (FIG. 4) until the keeper 66 is fully latched, as shown in FIG. 8. Simultaneous with the latching of the roller keeper 66, the forward movement of the rack 55 urges the roller keeper 143 against the latch finger 142, camming the latch arm 140 upward and in the counterclockwise direction, as shown in FIG. 5, until the keeper 142 is fully latched (FIG. 9).

As a consequence of the just described operation, the apparatus is in its charged condition, as represented by the FIGS. 7-9. Accordingly, while the contacts 23 remain open, the spring 60 has now been fully loaded (compressed) (F I07 7), and is held in this condition due to the latching of the rack 55 in its forward position by the latch arm 140 and keeper 143 combination, as observed most clearly in FIG. 9. The finger 142 is maintained in its latching relationship with the roller keeper 143 due to the pressure exerted by the spring-biased release means 145, the extension 147 being adjacent and slightly rearward the flange member 58. It is to be noted that as the latch arm 140 is pivoted upward, as shown in FIG. 5, the resulting pivotal movement of the release means 145 enables the flange 58 on the bracket 57 to pass under the extension 147 as the rack 55 (and bracket 57) travels forward.

In a similar manner, the finger 104 has fully latched the roller 66 (FIG. 8), the carriage plate 63 therefore being held in its forwardmost position, and the gears 61 and 62 are retained against linear travel in the rearward direction, The spring biasing of the latch arm 101, as well as the pivotal engagement of the cam surface 107 against the cam follower portion of arm 101, maintains the plate 63 and gears 61 and 62 in this latched position.

Now, to close the vacuum interrupter contacts 23, the shaft 80 is rotated in the clockwise direction until the boss 76 engages the rear projection 59 of the bracket 57 (as shown in FIG. 10). Since the shaft 80 is journaled for rotation within the axial bore of the gear 70, and since the boss 72 is disengaged during this clockwise rotation from the shoulder 71, the gear 70 (and consequently the rack 55) remain stationary. Further clockwise rotation of the shaft 80 then drives the slidingly mounted bracket 57 in the rearward direction (as pictured in FIG. 12), forcing the extension 58 against the projection 147, pivoting the the release means 145 away from engagement with the latch finger 142, and releasing the latch arm 140 from latching engagement with the roller keeper 143 on the rack 55. Spring 200 is then employed to return the bracket 57 to its original position.

As a consequence of this release step, the rack 55 is freed, and the power of the compressed spring 60 forces the rack 55 in the rearward direction. Since the carriage plate 63 is maintained in latched relationship by the latch arm 101 during this phase of the cycle, rearward travel of the rack 55 rotates the gears 61 and 62 and drives the rack 45 and drive rod 411 forward. In this regard it should be pointed out that the compression spring 60 must be strong enough to overcome the force of the spring 50. The resultant forward motion of the rack 45 and drive rod 41 thus compresses or loads the spring 50, and reciprocates the rod 22 to close the contacts 23 (FIG.

The automatic and manual tripping or opening operation of the contacts 23 is now described and specific reference to FIG. 11. The solenoid 131 affixed to the underside of the cover plate 17, for example, is coupled to fault sensing or relay circuitry 35, and has its translatable plunger 132 coupled to a wire 130 which, in turn, is connected to projection 109. When an overload or fault condition is sensed by the relay circuitry 35, a resulting output signal from the circuitry translates the plunger 132 inward, and pulling the wire 130 to pivot the pro jection 109 in the clockwise direction, forcing the toggle 111 against the leg portion 108, and pivoting the means 105 out of engagement with the latch finger. The latch finger 104 is then cammed out of engagement with the roller keeper 66, and the power of the compressed spring 50 forces the freed rack 45, drive rod 41, and carrier rod 22 rearward, thereby to open the contacts 23, interrupt the circuit in which the apparatus is inserted, and return the mechanism to the inactive state illustrated in FIG. 3. Various types of relay circuitry known in the art may be employed for the circuitry 35 coupled to the solenoid 131 which is responsive to excessive current conditions. As one example, however, the relay circuitry described in copending US. Pat. application, Ser. No. 788,773, assigned to the assignee of the present application, may be employed. It is to be noted that the actuator mechanism 40 is trip-free in that the contacts 23 may always be automatically tripped open at any point in the operating cycle.

Manual tripping or opening of the contacts 23 is also provided by rotating the shaft 80 in the counterclockwise direction as illustrated in FIG. 11 to force the boss 76 into engagement with the leg 109, the resulting pivotal movement of the trip release means 105 opening the contacts 23 in the mannerjust described.

Various modifications of the disclosed embodiment as well as additional embodiments may become apparent to those skilled in the art after reviewing the foregoing description without departing from the spirit and scope of the invention as defined by the following claims.

What is claimed is:

l. Actuating mechanism for reciprocatively translating a movable contact carrier rod for respective engagement and disengagement with electrically conductive means, said actuating mechanism comprising:

a. a first drive rod mounted for reciprocating movement along a first linear path, said first drive rod coupled to said movable contact carrier rod for advancing and retracting said contact carrier rod into said engagement and disengagement,

b. a second drive rod mounted for reciprocating movement along a second linear path parallel to said first linear path,

c. first means for urging said second drive rod in one direction along said second path,

d. second means for urging said second drive rod in an opposite direction along said second path while simultaneously urging said first drive rod in said one direction along said first linear path to a forwardmost position, thereby to advance said movable contact carrier rod into engagement with said electrically conductive means, said second means comprises a pair of racks respectively coupled to said first and second drive rods, at least one rotary gear simultaneously engaging said pair of racks, and a first spring means, when compressed, for urging said rack coupled to said second drive rod in said opposite direction along said second path; said latch means also preventing the linear travel of said rotary gear when said second drive rod is being urged in said opposite direction; and further including a second spring means coupled to said LII rack coupled to said first drive rod which, when compressed, urges said front drive rod in said opposite direction along said first path, thereby to disengage said movable carrier rod from said electrically conductive means, said second spring being compressed by the travel of said first drive rod in said one direction, said first spring means being compressed by the travel of said second drive rod in the said one direction,

e. latch means for holding said first drive rod in said forwardmost position, and

f. trip means for releasing said latch means, thereby to allow disengagement of said carrier rod from said electrically conductive means.

2. The apparatus as described in claim 1 including another latch means for holding said first spring means in the compressed state, second trip means for releasing said another latch means, and wherein said first mentioned latch means also holds said second spring means in the compressed state.

3. The apparatus as described in claim 2 wherein said first urging means comprises another rotary gear secured against linear motion engaging said rack coupled to said second drive means and an elongated shaft coupled to said another rotary gear for rotating said another gear and urging said rack in said one direction.

4. The apparatus as described in claim 3 wherein said second mean comprises two rotary gears simultaneously engaging said pair of racks, and a carriage plate coupled to said two rotary gears having a roller keeper disclosed thereupon, said first mentioned latch means adapted to engage said roller keeper.

5. Circuit interrupting apparatus, comprising:

a. a pair of coaxially disposed contact carrier rods, one of said rods being fixed, the other of said rods being mounted for reciprocating motion for engagement and disengagement with said fixed rod,

b. first rack means coupled to said reciprocatively mounted rod,

. first spring means coupled to said first rack means, said first spring means being compressed in response to the advancement along a first linear path of said first rack means,

d. second rack means operatively coupled to said first rack means by rotary gear means simultaneously engaging said first and second rack,

e. second spring means coupled to said second rack means, said second spring means being compressed in response to the movement in a forward direction along a second linear path parallel to said first linear path of said second rack means, said second spring means, when compressed, powering said second rack means in a rearward direction along said second linear path,

. means for advancing said second rack to a forwardmost position, thereby to compress said second spring means,

g. means for holding said rotary gear means against linear motion when said second rack is moving in said rearward direction, thereby to advance said first rack in a forward direction along said first linear path, whereby said reciprocatively mounted rod is advanced into engagement with said fixed rod, and said first spring is compressed, and

h. means for holding said reciprocatively mounted rod in engagement with said fixed rod and holding said first spring in said compressed state.

6. The apparatus as described in claim 5 wherein said means for holding said rotary gear means against linear motion and the means for holding said reciprocatively mounted rod in engagement with said fixed rod comprises a roller keeper cou pled to said rotary gear, and a pivotally mounted latch for engaging said roller keeper as said second rack is advanced to its forwardmost position.

7. The apparatus as described in claim 6 including means for tripping said latch out of engagement with said roller keeper, thereby to release said rotary gear for linear travel and release said first spring from its compressed condition, whereby said reciprocatively mounted rod is urged out.

8. The apparatus as described in claim 7 wherein said tripping means is responsive to excessive current conditions through said coaxially disposed contact carrier rods.

9. The apparatus as described in claim 8, including separate latch means for holding said second rack in said forwardmost position, and separate trip means for manually releasing said separate latch means.

10. Circuit interrupting apparatus, comprising:

a. a pair of laterally spaced conductive terminals,

b. a pair of coaxially disposed contact carrier rods respectively electrically connected to each of said conductive terminals, one of said carrier rods reciprocatively mounted for engagement and disengagement with the other of said carrier rods,

0. a substantially evacuated chamber,

d. contact faces disposed on respective one ends of said carrier rods within said substantially evacuated chamber,

e. a pair of racks mounted for respective reciprocating motion in first and second linear paths, one of said racks operatively coupled to said reciprocatively mounted carrier rod,

f. a rotary gear intermediate and having its teeth simultaneously mesh with said pair of racks said rotary gear being freed for linear travel along a path parallel to said first and second linear paths,

g. first and second compression springs respectively coupled to said pair of racks, each spring being compressed in response to the advancement of the coupled rack along the respective linear path in one direction and, when compressed, providing means for powering the coupled rack along the respective linear path in the opposite direction,

h. means for advancing said other rack in said one direction to a forwardmost position, said means comprising another rotary gear operatively engaged with said other rack, and a rotatable shaft journaled for rotation with said another rotary gear having means affixed thereto for rotating said another rotary gear,

i. first latch means for holding said other rack in said forwardmost position, said first latch means comprising a pivotally mounted latch adapted to engage roller keeper connected to said another rack,

j. first trip means for releasing said latch from said roller keeper, said first trip means being actuated by the rotation of said rotatable shaft,

k. second latch means for holding said first-mentioned rotary gear from linear motion while said other rack is powered in said opposite direction, thereby to advance said one rack in said one direction and advance said reciprocatively mounted contact carrier rod into engagement with said other contact carrier rod, said latch means comprising a pivotally mounted latch arm engaging another roller keeper coupled to said first mentioned rotary gear, and

I. second trip means for releasing said second latch means,

said second trip means being actuated in response to excessive current through said spaced conductive terminals. 

1. Actuating mechanism for reciprocatively translating a movable contact carrier rod for respective engagement and disengagement with electrically conductive means, said actuating mechanism comprising: a. a first drive rod mounted for reciprocating movement along a first linear path, said first drive rod coupled to said movable contact carrier rod for advancing and retracting said contact carrier rod into said engagement and disengagement, b. a second drive rod mounted for reciprocating movement along a second linear path parallel to said first linear path, c. first means for urging said second drive rod in one direction along said second path, d. second means for urging said second drive rod in an opposite direction along said second path while simultaneously urging said first drive rod in said one direction along said first linear path to a forwardmost position, thereby to advance said movable contact carrier rod into engagement with said electrically conductive means, said second means comprises a pair of racks respectively coupled to said first and second drive rods, at least one rotary gear simultaneously engaging said pair of racks, and a first spring means, when compressed, for urging said rack coupled to said second drive rod in said opposite direction along said second path; said latch means also preventing the linear travel of said rotary gear when said second drive rod is being urged in said opposite direction; and further including a second spring means coupled to said rack coupled to said first drive rod which, when compressed, urges said front drive rod in said opposite direction along said first path, thereby to disengage said movable carrier rod from said electrically conductive means, said second spring being compressed by the travel of said first drive rod in said one direction, said first spring means being compressed by the travel of said second drive rod in the said one direction, e. latch means for holding said first drive rod in said forwardmost position, and f. tRip means for releasing said latch means, thereby to allow disengagement of said carrier rod from said electrically conductive means.
 2. The apparatus as described in claim 1 including another latch means for holding said first spring means in the compressed state, second trip means for releasing said another latch means, and wherein said first mentioned latch means also holds said second spring means in the compressed state.
 3. The apparatus as described in claim 2 wherein said first urging means comprises another rotary gear secured against linear motion engaging said rack coupled to said second drive means and an elongated shaft coupled with said another rotary gear for rotating said another gear and urging said rack in said one direction.
 4. The apparatus as described in claim 3 wherein said second mean comprises two rotary gears simultaneously engaging said pair of racks, and a carriage plate coupled to said two rotary gears having a roller keeper disposed thereupon, said first mentioned latch means adapted to engage said roller keeper.
 5. Circuit interrupting apparatus, comprising: a. a pair of coaxially disposed contact carrier rods, one of said rods being fixed, the other of said rods being mounted for reciprocating motion for engagement and disengagement with said fixed rod, b. first rack means coupled to said reciprocatively mounted rod, c. first spring means coupled to said first rack means, said first spring means being compressed in response to the advancement along a first linear path of said first rack means, d. second rack means operatively coupled to said first rack means by rotary gear means simultaneously engaging said first and second rack, e. second spring means coupled to said second rack means, said second spring means being compressed in response to the movement in a forward direction along a second linear path parallel to said first linear path of said second rack means, said second spring means, when compressed, powering said second rack means in a rearward direction along said second linear path, f. means for advancing said second rack to a forwardmost position, thereby to compress said second spring means, g. means for holding said rotary gear means against linear motion when said second rack is moving in said rearward direction, thereby to advance said first rack in a forward direction along said first linear path, whereby said reciprocatively mounted rod is advanced into engagement with said fixed rod, and said first spring is compressed, and h. means for holding said reciprocatively mounted rod in engagement with said fixed rod and holding said first spring in said compressed state.
 6. The apparatus as described in claim 5 wherein said means for holding said rotary gear means against linear motion and the means for holding said reciprocatively mounted rod in engagement with said fixed rod comprises a roller keeper coupled to said rotary gear, and a pivotally mounted latch for engaging said roller keeper as said second rack is advanced to its forwardmost position.
 7. The apparatus as described in claim 6 including means for tripping said latch out of engagement with said roller keeper, thereby to release said rotary gear for linear travel and release said first spring from its compressed condition, whereby said reciprocatively mounted rod is urged out.
 8. The apparatus as described in claim 7 wherein said tripping means is responsive to excessive current conditions through said coaxially disposed contact carrier rods.
 9. The apparatus as described in claim 8, including separate latch means for holding said second rack in said forwardmost position, and separate trip means for manually releasing said separate latch means.
 10. Circuit interrupting apparatus, comprising: a. a pair of laterally spaced conductive terminals, b. a pair of coaxially disposed contact carrier rods respectively electrically connected to each of said conductive terminals, one of said cArrier rods reciprocatively mounted for engagement and disengagement with the other of said carrier rods, c. a substantially evacuated chamber, d. contact faces disposed on respective one ends of said carrier rods within said substantially evacuated chamber, e. a pair of racks mounted for respective reciprocating motion in first and second linear paths, one of said racks operatively coupled to said reciprocatively mounted carrier rod, f. a rotary gear intermediate and having its teeth simultaneously mesh with said pair of racks said rotary gear being freed for linear travel along a path parallel to said first and second linear paths, g. first and second compression springs respectively coupled to said pair of racks, each spring being compressed in response to the advancement of the coupled rack along the respective linear path in one direction and, when compressed, providing means for powering the coupled rack along the respective linear path in the opposite direction, h. means for advancing said other rack in said one direction to a forwardmost position, said means comprising another rotary gear operatively engaged with said other rack, and a rotatable shaft journaled for rotation with said another rotary gear having means affixed thereto for rotating said another rotary gear, i. first latch means for holding said other rack in said forwardmost position, said first latch means comprising a pivotally mounted latch adapted to engage roller keeper connected to said another rack, j. first trip means for releasing said latch from said roller keeper, said first trip means being actuated by the rotation of said rotatable shaft, k. second latch means for holding said first-mentioned rotary gear from linear motion while said other rack is powered in said opposite direction, thereby to advance said one rack in said one direction and advance said reciprocatively mounted contact carrier rod into engagement with said other contact carrier rod, said latch means comprising a pivotally mounted latch arm engaging another roller keeper coupled to said first mentioned rotary gear, and l. second trip means for releasing said second latch means, said second trip means being actuated in response to excessive current through said spaced conductive terminals. 